How to insert an element into an array with JavaScript

by Janeth Kent Date: 20-08-2021 javascript

In this brief tutorial you will learn how to insert one or more elements into an array with JavaScript.

For this we will use the splice function.

The splice function will not create a new array when used, but will modify the existing array. The syntax of the splice function, included in Array elements, is as follows:

arr.splice(index, deleteElements, insertElement1, insertElement2, ..., insertElementN)

Let's start from the following example array:

const numbers = [0, 1, 2, 3, 4, 6, 9];

What we are going to do is to insert element 5 in the fifth position of the array.

To do this we would use the splice function like this:

numbers.splice(5, 0, 5);

Now, if we do a console.log of the array numbers, we get the following:

(8)[0, 1, 2, 3, 4, 5, 6, 9]

Now we are going to insert multiple elements, so we are going to add the values 7 and 8. In this case we simply indicate the elements to be inserted, one after the other:

arr.splice(7, 0, 7, 8);

If, again, we do a console.log of the array numbers, we get the following:

(10)[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]

by Janeth Kent Date: 20-08-2021 javascript hits : 2550  
Janeth Kent

Janeth Kent

Licenciada en Bellas Artes y programadora por pasión. Cuando tengo un rato retoco fotos, edito vídeos y diseño cosas. El resto del tiempo escribo en MA-NO WEB DESIGN END DEVELOPMENT.


Related Posts

How to make your own custom cursor for your website

When I started browsing different and original websites to learn from them, one of the first things that caught my attention was that some of them had their own cursors,…

Node.js and npm: introductory tutorial

In this tutorial we will see how to install and use both Node.js and the npm package manager. In addition, we will also create a small sample application. If you…

How to connect to MySQL with Node.js

Let's see how you can connect to a MySQL database using Node.js, the popular JavaScript runtime environment. Before we start, it is important to note that you must have Node.js installed…

JavaScript Programming Styles: Best Practices

When programming with JavaScript there are certain conventions that you should apply, especially when working in a team environment. In fact, it is common to have meetings to discuss standards…

Difference between arrow and normal functions in JavaScript

In this tutorial we are going to see how arrow functions differ from normal JavaScript functions. We will also see when you should use one and when you should use…

JavaScript Arrow functions: What they are and how to use them

In this article we are going to see what they are and how to use JavaScript Arrow Functions, a new feature introduced with the ES6 standard (ECMAScript 6). What are Arrow…

What is the difference between primitives types and objects in JavaScript?

In this short tutorial we are going to look at the differences between primitive types and objects in JavaScript. To start with, we're going to look at what primitive types…

How to get DOM elements with JavaScript

When you access any element of the DOM, it is usual to save it in a variable. This is something that at first might seem very simple, but if you…

How to reverse an array in JavaScript

In this tutorial we are going to see how you can change the order of the elements of an array so that they are inverted. You could use a loop…

How synchronize the scroll of two divs with JavaScript

In case you have two divs of different sizes you may sometimes want to scroll both at the same time but at different speeds depending on their size. For example,…

How to use the codePointAt method in JavaScript

The JavaScript codePointAt method has more or less the same function as the charCodeAt method, used to get the 16-bit Unicode representation of the character at a certain position in…

How to check if a value is a number in JavaScript

In this short tutorial we are going to look at the various methods that exist to find out if a value is a number in JavaScript.   1. Using the isNaN() function   One…

We use our own and third-party cookies to improve our services, compile statistical information and analyze your browsing habits. This allows us to personalize the content we offer and to show you advertisements related to your preferences. By clicking "Accept all" you agree to the storage of cookies on your device to improve website navigation, analyse traffic and assist our marketing activities. You can also select "System Cookies Only" to accept only the cookies required for the website to function, or you can select the cookies you wish to activate by clicking on "settings".

Accept All Only sistem cookies Configuration